2021 Fiscal Year Final Research Report

Phase I/II trial of carbon ion radiotherapy for breast cancer

Research Project

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Project/Area Number	18K07772
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Review Section	Basic Section 52040:Radiological sciences-related
Research Institution	Tokyo Women's Medical University
Principal Investigator	Karasawa Kumiko 東京女子医科大学, 医学部, 教授 (60214574)
Co-Investigator(Kenkyū-buntansha)	小此木範之国立研究開発法人量子科学技術研究開発機構, 放射線医学総合研究所重粒子線治療研究部, 医長(定常) (00750572) 平野明東京女子医科大学, 医学部, 准教授 (10349665) 神尾孝子東京女子医科大学, 医学部, 准教授 (20177570) 川井佐和 (河野佐和) 東京女子医科大学, 医学部, 助教 (80645820) 尾松徳彦国立研究開発法人量子科学技術研究開発機構, 放射線医学総合研究所分子イメージング診断治療研究部, 医長(定常) (90374280)
Project Period (FY)	2018-04-01 – 2022-03-31
Keywords	乳癌 / 炭素イオン線治療
Outline of Final Research Achievements	We conducted clinical trial of curative partial breast irradiation using carbon ion radiotherapy to patients with stage 0 and I breast cancer. The candidate of this study was patients with Tis-1N0M0 breast cancer aged 20 years and older. In this study, carbon ion partial breast irradiations were combined with standard systemic therapy and x-ray whole-breast irradiation. Phase I was a dose-escalation study and phase II was treated with the recommended dose determined in Phase I. The starting dose is 52.8 Gy (RBE). By April 2022, a total of 5 eligible cases were enrolled in phase I, and 10 eligible cases in phase II with a recommended dose of 60.0 Gy (RBE). As acute adverse effects more than grade 2, acute grade 2 radiation dermatitis was observed in 1 case. As late adverse effects, grade 3 pneumonia of unknown causality were observed in 1 case. The cosmetic results of breast were excellent in all cases. No local recurrences or metastases have been observed.
Free Research Field	放射線腫瘍学
Academic Significance and Societal Importance of the Research Achievements	乳がんは日本人女性で最も多いがんであり、根治のみならず切らずに治す低侵襲治療の要望も多い。今までの早期乳癌に対する炭素イオン線治療の研究では、対象を高齢者の低リスク患者に限定していたが、本研究により、20歳以上の全てのサブタイプの早期乳癌に対して、標準的補助療法との組み合わせで、非切除の根治乳癌治療が可能となるとしたら、併存症や高齢で手術切除に適さない患者、あるいは精神的理由などで手術が行えない患者、手術を希望しない患者にとっての恩恵となる。